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JEE Main20209 Jan 2020Morning ShiftChemistryChemical KineticsActual

For the following reactions A → 700 K Product A → catalyst 500 K Product It was found that the E a is decreased by 30 K J / m o l in the presence of catalyst. If the rate remains unchanged, the activation energy for catalysed reaction is (Assume pre-exponential factor is same)

Options

  1. A75   K J / m o l
  2. B105   K J / m o l
  3. C135   K J / m o l
  4. D198   K J / m o l

Correct answer

A. 75   K J / m o l

Step-by-step solution

K cat = K Ae - Ea 1 RT 1 = Ae - Ea 2 RT 2 Ea 1 T 1 = Ea 2 T 2   ;   Ea 1 = Ea 2 - 30 Ea 2 - 30 500 = Ea 2 700 5 Ea 2 = 7 Ea 2 - 210 Ea 2 = 210 2 = 105   kJ / mole Activation energy of the catalysed reaction = 105 - 30 = 75   kJ / mole .

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